Marine invasive species and their bioactive metabolites have become critical ecological issues in the Mediterranean Sea. In particular, the highly invasive green algae Caulerpa taxifolia and Caulerpa cylindracea are known to contain the bioactive sesquiterpene caulerpenyne (1) and the bisindolic alkaloid caulerpin (2), potentially acting as chemical stressors for native species. The recent spread of a variety of C. taxifolia, Caulerpa taxifolia var. distichophylla, also raises urgent questions about its chemical composition. Indeed, the only chemical data available for this alga are limited to the seasonal variations of caulerpenyne (1) in samples collected in the Eastern Mediterranean. In this study, we confirmed the presence of 1 also in C. taxifolia var. distichophylla collected along the Sicilian coast, while 2 was not detected in the alga. However, caulerpin (2) was found both in a Mediterranean specimen of C. taxifolia, and at a much higher level in the congeneric C. cylindracea. This suggests that C. taxifolia var. distichophylla differs from C. taxifolia in its secondary metabolism, potentially exerting dissimilar chemically mediated impacts on native biota. Further chemical investigations on the terpenoidic content of C. taxifolia var. distichophylla led to isolate and identify squalene 2,3 oxide (3), phytol (4), and plastoquinone (5), along with the two unreported sesquiterpene lactones 6 and 7. Finally, chemoecological assays clarified that caulerpenyne (1) at its natural concentration in C. taxifolia var. distichophylla elicits avoidance responses in native shrimp, although sensitization was a prerequisite to significantly induce food rejection.

海洋入侵物种及其生物活性代谢物已成为地中海的关键生态问题。特别是，已知高侵袭性绿藻Caulerpa taxfolia和Caulerpa cylindracea含有生物活性倍半萜类花椰菜炔 ( 1 ) 和双吲哚生物碱花椰菜 ( 2 )，可能充当本地物种的化学应激物。最近传播的各种C.taxfolia，Caulerpa taxfolia var。distichophylla，也提出了关于其化学成分的紧迫问题。事实上，该藻类唯一可用的化学数据仅限于花椰菜的季节性变化（1) 在东地中海收集的样本中。在这项研究中，我们证实了1在C.taxfolia var. 中也存在。distichophylla沿西西里海岸收集，而2在藻类中未检测到。然而，caulerpin（2）被发现无论是在地中海试样C. taxifolia，并且在同类高得多的水平C. cylindracea的。这表明C.taxfolia var. distichophylla不同于C. taxifolia在其次生代谢中，可能对天然生物群产生不同的化学介导影响。对C.taxfolia var.萜类化合物含量的进一步化学研究。distichophylla导致分离和鉴定角鲨烯 2,3 氧化物 ( 3 )、植醇 ( 4 ) 和质体醌 ( 5 )，以及两种未报告的倍半萜内酯6和7。最后，chemoecological测定澄清caulerpenyne（1在其天然浓度）C. taxifolia变种 铁树属 引起本地虾的回避反应，尽管致敏是显着诱导食物排斥的先决条件。